In Glasgow, one of the old tabloid wheezes used to be for editors to hire a vacant shop in one of the less salubrious quarters of the city, nail a sign announcing a new business operating on a variant of the pawn-shop model, add a few CCTV cameras and undercover journalists as staff, then sit back and wait for the customers and stories to roll in.

In short order, various gentlefolk would lurch into the premises carting whatever items in their vicinity couldn’t be paid for, nailed down or missed, in the hope of converting them into cash.

Within days, the whole sad gutter opera was played out in the national press with mug shots and photos of the “goods” being printed for all to devour. The piece usually ended on an ominous yet oddly hopeful note, telling readers that a “dossier was handed to the police last night”.

The model of an accepted criminal wrong had been corrected by the intervention of the accepted model of the tabloid investigative journalism right. Justice prevailed. Everyone could sleep easy.

The problem for me with the sting was that we never sorted out the really bad from the totally desperate. It was the fast-food equivalent of investigative journalism – lots of calories, no real substance. But neither side would learn: the stunt was – and is – repeated regularly.

Now five years on, Channel 4 and The Daily Telegraph teamed up to do the same again. Predictably – and in line with the Glasgow pawn-shop sting – a ragged but compelling programme ensued.

The undercover reporters created a fake communications agency called PMR, which they claimed was based in Hong Kong. A total of 12 MPs with “significant outside interests” were invited to apply for jobs with the agency, which had “plenty of money” and wanted to hire “influential British politicians to join its advisory board”.

According to Channel 4: “Half of those approached didn’t respond. One said he wanted to check us out in Hong Kong so we took it no further. And another said he just wasn’t that interested. Of the others, two stood out – Sir Malcolm Rifkind and Jack Straw.”

This was a shock since Rifkind and Straw are regarded as pair of polished old foxes who squeak with apparent probity when they walk. They wear the patina of certain old buffers from Belgravia, fully paid-up members for life of the “Turn left when you board the plane for First Class, sir” club.

On camera

The programme started with shaky footage from a digital pinhole camera of Malcolm Rifkind sitting in a rather bare office, vaguely laying on the charm for his guests.

Speaking in a less cascading Edinburgh soft-brogue than normal he quickly cut to the chase in language everyone could understand: “I am self-employed, so nobody pays me a salary. I have to earn my income, but when I am not doing something I can do what I like.”

He described his fees for a half day’s work as “somewhere in the region of £5,000 to £8,000, something like that”.

Jack Straw was rather more elliptical in his reply when the journalists came calling to his parliamentary abode: “I am an adviser to a firm you probably won’t have heard of, but it’s one of Britain’s biggest soft commodity traders,” he said. “I got in to see the relevant director general and his officials in Brussels … and we got the sugar regulations changed.”

“It’s public that the regulations have been changed, but the best way of dealing with these things is under the radar.”

With regard to fees, he said: “Normally, if I’m doing a speech or something it’s £5,000 a day, that’s what I charge.”

Pre-emptive strikes

Before the programme was even broadcast the two old sluggers had taken to Radio 4 to start chucking counter-versions, explanations and official statements into the mix in the hope of defending themselves. In summary, both claimed they’d done nothing wrong, that they’d been set up and anyone offended should read the rules … really read them.

By the day’s end they’d been suspended from their parties and told they’d be subject to scrutiny. Like the Glasgow-sting wheeze, this all felt wearily, achingly, numbingly familiar. And that’s a shame.

There was a time when MPs so obviously operating in the grey area between rules, guidelines and laws and caught on camera would have resigned in utter disgrace in a heartbeat – albeit Rifkind has since said he will step down as an MP and resigned his position as chair of the Intelligence Select Committee (ISC). They would have recognised the perception had doomed them because reputation and the friends it earned was jealously guarded for the best of reasons and not traded on lightly.

Given Rifkind’s position on the ISC, you’d have assumed he’d have avoided anyone from China like the plague simply because of obvious dangers. Equally Jack Straw, regarded as at the very least a fairly fortunate Blair/Iraq-era survivor, might have laid low this side of the general election to ensure a smooth slide across the palace of Westminster to don the robes in the Lords.

Yet there they were, giving us a glimpse into their expensive yet curiously dead-eyed little world, where a flood of cash seemed needed in the most pedestrian of ways to fund their future retirement.

Now that Rifkind has gone, all eyes will be on Straw – who was already standing down as an MP in May. He may fight like hell by claiming he was the victim of journalistic entrapment. It’s the clever strategy and it worked for a company many years ago in the US who sued a TV network when they were caught by undercover reporters flogging rancid food. The jury agreed the journalists were the liars in the case and awarded millions to the food company. Public interest investigative journalism came second.

How they think they should live

I suspect many fellow MPs would have been wary of knifing Rifkind and Straw. It’s a common gripe in the corridors of the Commons that MPs’ salary of £67,000 or thereabouts is miserly compared to the average US senator being paid $174,000 (around £113,000).

The complaints were louder before the expenses scandal blew up, but rest assured they can still be heard. People can get used to living in London fast and it takes big bucks.

After watching the documentary I recalled that a good few years ago, I met someone very close to a former prime minister. The meeting was formal and parts were agreed to be off the record. I asked this highly placed source what the former PM’s plans were.

The source gloomily replied that the PM had to scan the horizon for lucrative income streams because as a former resident of Number 10 and international statesman, people expected him to live a certain way and that cost a lot of money.

My source shrugged, threw his hands up and looked sad. Only later was I stuck by the fact there was never, not even for a second, any hesitation in considering this as the only option. All behaviour, it was inferred, even that involving meetings which might be perceived as bordering on the dodgy and even a bit pathetic, was deemed worthy of consideration.

Austerity for those at the very, very top was never remotely countenanced.